Restrictive Cardiomyopathy

History

Fact

Explanation

Dyspnoea [1]

This is a disease characterized by impaired ventricular filling and reduced diastolic volume in the presence of normal systolic function and normal or near normal myocardial thickness. Because of that ejection fraction is reduced which leads to the pulmonary congestion and reduced blood gas exchange. [1], [2], [4]

Orthopnea[1]

When the patient is lying down pulmonary congestion increases upto a level where the patient feels difficulty in breathing when lying down and but it relieves in a sitting up position.[1], [2], [4]

Peripheral edema[1]

When the heart fails to maintain cardiac output and peripheral tissue perfusion there is expansion of extracellular fluid volume secondary to the salt and water retention.[1], [2], [4]

Ascitese[1]

This will occur with right heart failure and volume overload due to the neurohormonal and other compensatory mechanisms. [1], [2], [4]

Fatiguge[1]

Exertional fatigue occurs due to the under - perfusion of the skeletal muscles. [3],[4]

Atypical chest pain [1]

Occurs due to ischemia. Angina does not occur except in the presence of cardiac amyloidosis. [1],[4],[5]

Syncopal attack [1]

Normal architecture of the cardiac muscle is disrupted and conduction tissues system get disorganize and cause atrial fibrillations, more common in amyloidosis and sarcoidosis. [1][4][5].

Sudden death[1]

Even though ventricular fibrillation is uncommon this can occur in amyloidosis. [4]

Examination

Fact

Explanation

S3[1][2]

Best heard at the apex, occurs due to the left ventricular dysfunction Later S3, low pitched, “triple rhythm” will be heard. [1],[2]

Murmur [3]

There can be murmurs secondary to the myocardial disease such as an apical mid- diastolic murmur - in localised pericardial constrictions. Systolic murmurs due to atrioventricular valve regurgitation due to the endocardial disease. [3]

Jugular venous pressure [4]

External or internal jugular vein may be useful in the assessment of mean venous pressure and pulse contour. In restrictive cardiomyopathy due to the right heart failure, jugular venous pressure gets elevated. X and Y dips become less brief, may have conspicuous A wave or V wave. [1],[4]

Ascites [3]

This will occur with right heart failure and volume overload due to the neurohormonal and other compensatory mechanisms. [3]

Pitting edema [2]

When the heart fails to maintain cardiac output and peripheral tissue perfusion there is expansion of extracellular fluid volume secondary to the salt and water retention.[3]

Differential Diagnoses

Fact

Explanation

Constrictive pericarditis [1]

The differentiation of restrictive cardiomyopathy and constrictive pericarditis has been a perennial problem in clinical cardiology. These are the important points frequently helpful in favouring constrictive pericarditis over restrictive cardiomyopathy. History of active pericarditis and examination features of: Freidreich’s sign, paradoxical pulse. ECG will show an absence of intraventricular conduction defect, Chest radiograph—pericardial calciﬁcation, CT/MRI—thickened pericardium, Echocardiogram—septal notch, Doppler—ventricular interdependence, Cardiac catheterisation—close equilibration of diastolic pressures, Biopsy—absence of amyloid or other inﬁltrative disease. [1]

Aortic stenosis [2]

In this aortic valve get stenosed and present with features of cardiac failure. [2]

Cardiac temponade[3]

In this disease ventricular filling is impaired and cardiac function is compromised and cause symptoms as dyspnea, tachycardia, and tachypnea. [3]

Hypertrophic cardiomyopathy[4]

In this ventricular filling is impaired due to the hypertrophic cardiac muscles. [4]

Orthostatic hypotension [5]

In this syncopal attacks occurs due to the inability to maintain adequate blood pressure in upright position. [5]

Investigations - for Diagnosis

Fact

Explanation

Chest radiograpy [1], [2], [3]

Done mainly to exclude constrictive pericarditis. Cardiac size is usually normal. Atrial enlargement is present if there is atrioventricular valvular regurgitation. Pulmonary congestion is often seen, as well as interstitial edema, with Kerley B lines in the more severe cases. Pleural effusions may also occur. [1], [2], [3]

Electrocardiogram (ECG) [1], [2], [3]

Shows nonspecific ST- and T-wave abnormalities[1], [2], [3]

Echo-cardiogram (Echo) [1], [2], [3]

On Doppler echocardiography, the pattern of mitral-inflow velocity in restrictive cardiomyopathy is typically one of increased early diastolic filling velocity (>1.0 m per second), decreased atrial filling velocity (<0.5 m per second), an increased ratio of early diastolic filling to atrial filling (>2), a decreased deceleration time (<150 msec), and a decreased isovolumic relaxation time (<70 msec) [1], [2], [3]

Cardiac catheterization[1], [2], [3]

The characteristic hemodynamic feature is a deep and rapid early diastolic decline of ventricular pressure , with a rapid early diastolic rise to a plateau. This is the so-called dip and plateau or square-root sign and is manifested in the atrial-pressure tracing as a prominent Y descent followed by a rapid rise to a plateau.[1], [2], [3]

Myocardial biopsy[1], [2], [3]

This is a nearly certain method of diagnosing cardiac amyloidosis. Should be considered for patients in whom the diagnosis is not clear by other methods of evaluation. [1], [2], [3]

Management - General Measures

Fact

Explanation

Management of heart failure [1]

Diuretics are used to treat venous congestion in the pulmonary and systemic circulation. Their excessive use may reduce ventricular filling pressures, leading to decreased cardiac output and symptoms of fatigue and lightheadedness, with signs of hypotension and hypoperfusion.
Digoxin should be used with caution, since it is potentially arrhythmogenic, particularly in patients with amyloidosis. [1]

Management of atrial fibrillation [1]

Medical cardioversion is performed with amiodarone. Implantation of a pacemaker can also be performed. Anticoagulation with warfarin as thromboprophylaxis is performed due to the risk of embolic complications. [1]

Management - Specific Treatments

Fact

Explanation

Management of Cardiac Amyloidosis [1]

The prognosis with primary systemic amyloidosis remains poor. Chemotherapy has dramatic benefits, with improvement in cardiac as well as systemic manifestations in specific cases. Combination of melphalan, prednisone, and colchicine was advantageous for patients whose major manifestations of amyloid disease were other than cardiac or renal. When transplantation has been performed to treat cardiac amyloidosis, recurrence in the transplanted heart can occur. [1]

Medical therapy with corticosteroids and cytotoxic drugs is appropriate during the early phase of Loeffler's endocarditis and improves symptoms and survival. Surgical therapy, of replacement of the mitral or tricuspid valves by excision of the fibrotic endocardium is palliative in the fibrotic stage of the disease but may provide symptomatic improvement. [1]

Symptomatic medical management - Diuretics (Frusemide) [2],[3]

Used to reduce pulmonary and systemic congestion. Diuretics act on kidney to inhibit the sodium-potassium-chloride cotransporter in the thick ascending limb. Inhibition of this pump can lead to a significant increase in the distal tubular concentration of sodium, reduced hypertonicity of the surrounding interstitium, and less water reabsorption in the collecting duct. This altered handling of sodium and water leads to both diuresis and natriuresis. [2],[3]

Symptomatic medical management -Nitrates [2],[3]

Used for the treatment of concomitant angina or relief of dyspnoea. Nitrates release Nitrous Oxide which relaxes the vascular smooth muscles. [2],[3]

Symptomatic medical management -
Beta-lockers(Carvedilol) [2],[3]

Beta-blockers bind to beta-adrenoceptors located in cardiac nodal tissue, the conducting system, and contracting myocytes. The heart has both β1 and β2 adrenoceptors, although the predominant receptor type in number and function is β1. These receptors primarily bind norepinephrine that is released from sympathetic adrenergic nerves. Additionally, they bind norepinephrine and epinephrine that circulate in the blood. Therefore, beta-blockers cause a decrease in heart rate, contractility, conduction velocity, and relaxation rate. These drugs have an even greater effect when there is elevated sympathetic activity. Therefore it improves the functional class and leads to less worsening of heart failure. [2],[3]

Guidelines for the diagnosis and treatment of chronic heart failure: executive summary (update 2005): The Task Force for the Diagnosis and Treatment of Chronic Heart Failure of the European Society of Cardiology. European Heart Journal [online] 2005 April, 26(11):1115-1140 [viewed 30 June 2014] Available from: doi:10.1093/eurheartj/ehi204